Power-saw.



F. L. BRADLEY.

POWER SAW.

APPLIouxoN IILBD JULY s. 1012.

Patentedl Aug. 13, 1912.

i same, it is obvious that the saw will pulll UNITED ySTATES; PATENT OFFICE.

FRED L.l BRADLEY, 0F LOS ANGELES, CALIFORNIA. j,

POWER-SAW.

Specication of Letters Patent.

Patented Aug. 13, 1912.

Application tiled July 9, 1912. Serial No. 708,535. I

To all lwhom it may concern.

Be it known that I, FRED L. BRADLEY, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles, State of California, have invented new and useful Improvements in Power-Saws, of which the following is a specification.

This invention relates to the class of power saws more commonly known as scroll or jig saws, and it consists primarily in a novel application of a mechanical movement in such a manner as to provide a saw in which various difiiculties heretofore encountered are completely obviated.

One of the advantages of the present machine is the provision of a'simple mechanism for the lengthening and shortening of the stroke of the saw, this being accomplished through the medium of a thumb nut while the machine either is running or stationary.' The method of adjusting the stroke is such that practically, t-he same quantity'of power is at the disposal of the saw on a short stroke as on a long stroke. The reciprocating frequency remaining the heavier on a short stroke and will therefore cut through heavier material than is possible on the long stroke. On the other hand, the long light stroke admits of extremely fast work in light easily cut material.

Another of the salient features of the device is the relative arran ement of the power shaft and-the saw bla e, this arrangement being facilitated by the peculiar mechanical movement used'to connect the shaft with the saw. In most of the power saws of 'this class now in use the shaft is'journaled at right angles to the saw, so that the flexible power shaft usually used to s upply power to the machine extends radially from the axis about which the saw blade must be turned in order to cut curved figures inthe work. If the saw is turned through a complete revolution the shaft is correspondingly twisted and the saw must be removed from the work and turned back to its initial position. In the present device the flexible power shaft extends with its axisparallel to the length of the saw and any turning of the saw does not twist the shaft, but merely affects its position rotationally withreference to the stationary part of the machine.

In the accompanying drawings: Figure 1 is a longitudinal section showing the construction of the device. Fig. 2 is an enlar-ged section taken on line 2 2 of Fig. 1. Fig. 3 is an enlar ed end view taken from the right hand en Fig. 1.

Referring now particularly to the drawings, 5 desi ates a 'case of suitable construction which also forms the central vframe work of the machine. This case is provided with a circular handle member 6 extending from one end, the handle being hollow for the accommodation of shaft 7 therein. Shaft 7 extends beyond the end of the handle as at 8 and is connected in any suitable manner to a iexible shaft 9 through which power is supplied to the machine. The direct-ion of rotation of the shaft is of no consequence.

Mounted on the inner end of shaft 7 inside of casing 5 is a disk 10 having. a rim 11 of circular cross section. This disk iS mounted on the shaft in a peculiar manner, not being rigidly secured thereto. A slot 12 in the disk encircles shaft 7, the slot being of such a configuration as shown in Fig. 2, that its longitudinal walls fit tightly against the shaft, while it allows of `some play of the disk on the shaft in the direction longitudinal of the slot. A pin 13 is passed centrally through .shaft 7 and into the disk in the position relative to the slot shown in Fig. 2, the disk being thus rotationally aflixed to the shaft and also being allowed an oscillatory movement around the axis of pin 13.

Mounted on shaft 7, and affixed thereto by means of a feather 14 allowing its lon gitudinal movement on the shaft and compelling the rotational movement therewith, is a collar 15 connected by means of a link of Fig. 1. 'Fig 4 is anV enlarged section taken on line 4-4 of 16 to disk l0 at a point adjacent to one of the ends of -slot l2. The collar is moved along the shaft. through the medium of a small yoke 35 engaging its outer face, the yo e bein mounted on a screw threaded rod 18 whic rojects out through case 5 and is provi ed with a with a groove .17 in thumb nut 19 on its outer end. The thumb` Mounted yon the lower part of casing 5.

and closing its otherwise open bottom is a member 25 having in it a longitudinal slot .26 in which reciprocating bar 27 is mounted.

This bar is provided with two rollers 28 mounted thereon and projecting upwardly, on on each side of circular rim 11 of the dis On account of the circular cross section of the rim, the horizontal distance occupied by it in its different angular ,positions between the rollers is always constant. The rollers may therefore be set closely on the rim, avoiding any possible lost motion. This could not be true of a rim having any but a circular cross section. By reducing the angle of inclination between the disk and a plane normal to the shaft the amount of movement of bar 27 may be reduced, this movement being reduced to nothing when the disk is placed at rightangles to the shaft, or in the normal plane. Mounted on the outer end of bar 27 is a saw blade 34: of usual configuration. This saw blade projects through a foot plate 29, pointed opening 30 being provided therein for that purpose. This foot plate is mounted on the end of an extension 31 of member 25 as is shown clearly in Figs. 3 and 4E. l The end of the extension is rounded off and projects into a V-'shaped' opening 32 in the foot plate. A set screw 33 is mounted on the part of the foot plate inclosing the end of the extension and projects into the extension as indicated in Fig. 3, the screw being on the axis of the rounded end of the extension so that the foot plate may be turned in the directions indicated by the double headed arrow in Fig. l and set in any desired position by the screw. This angular setting of the foot plate renders it possible to cut material uniformly at any desired angle. I

Having described my invention, I claim: 1. A power saw, comprising a frame, a shaft journaled in the frame, a reciprocating member mounted in the frame, the line of reciprocation being parallel to the shaft axis, mechanism whereby the member is re cipro'cated uponl the rotation of theshaft,

saw mountingmeans on the end of the re- Y ciprocating member, and a foot plate pivotally mounted on the frame and having an aperture for lthe' passage of the saw, the

pivotal axis of the plate being in the plane, 'I

yof a cut'made by the saw. Y

on vthe extension and having an aperture 'therein for the passage of the saw, the pivotal axis. of the plate being in the plane of cut of the saw.

In witness that I claim the foregoing I have hereunto subscribed my name this 1st' day .of July 1912. f

' FRED L. BRADLEY. Witnesses:

- ELwooD I-I. BARKELEW, JAMES T. BARKELEW. 

